In the recovery of oil from oil-containing formations, it usually is possible to recover only minor portions of the original oil in-place by the so-called primary recovery methods which utilize only the natural forces present in the formation. Thus, a variety of supplemental recovery techniques have been employed in order to increase the recovery of oil from subterranean formations. These techniques include thermal recovery methods, waterflooding and miscible flooding.
Particularly troublesome is the recovery of viscous oil from oil reservoirs which are relatively shallow. These reservoirs often contain low pressures and low temperatures. Steam flooding is often used to recover viscous oil from these reservoirs. Although cyclic steam flooding may be utilized, often the steam flooding method is insufficient to recover a substantial volume of the viscous oil.
Therefore, what is needed is a method for enhancing the effectiveness of a steamflood operation when recovering viscous oils from relatively shallow reservoirs where the temperatures and pressures are low.